Pattern mechanism for dobby looms



May 21, 1940.

J. A. TALBERT in AL 2,201,707 PATTERN MECHANISM FOR DOBBY LOOMS FiledApril 28, 1939 4 sheets-sh eet 1 i'mventors: a JOHN F). THLBERT 0NHL/RICE HENDRICK y 1940. J. A. TALBERT ET AL PATTERN MECHANISH FOR DOBBY LOOKS 4 Sheets-Sheet 2 Filed April 28, 1939 JOHN H. 7hLBsRT iMnu/e/cs HENDRICK ISrwentor May 21, 1940. J. A. TALBERT El AL v PATTERNmacrmmsu FOR DOBBY LOOMS Filed Apiil 28, 1939 4 Sheets-Sheet 3 9 JOHN H.TQLBEQT MRuE/cE HENDR/CK lhwgntor s Gttorneg y ,940. J. A. TALBERT ET AL2,201,707

PATTERN MECHANISM FO DOBBY LOOMS Filed Aril 28, 1939 4 Sheets$heet 4Mick "tors,

(Ittorneg Patented May 21, 1940 UNITED STATES PATENT OFFiCE John A.Talbert and Maurice Hendrick, Cliffside, N. 0.

Application April 28, 1939, Serial No. 270,587

4 Claims.

Heretofore, dobby looms have been equipped.

with exceedingly long pattern chains. In many instances, it has beennecessary to provide a chain link or bar for each pick in the pattern,even though the Weave might repeat itself every third or fourth pick.The cost of constructing and mounting a chain of this length has provedto be excessive. Also due to its length, much mill space is occupied bythe chain that might be otherwise used to an advantage.

It is, therefore an object of this invention to provide a patternmechanism for a dobby head comprising a pattern chain having a pluralityof linked bars therein for controlling the head, with means for movingthe chain forward for a plurality of picks and means for reversing thechain to a previously occupied position in time for it to control thenext successive pick. The chain will then move forward again until it isreversed as before. This type of pattern mechanism is particularlyimportant where a repeat weave is being controlled. The reversing of thechain for each repeat, causes the same bars to be used over and overagain as long as the repeat weave is woven, thereby shortening patternchains to a minimum.

It is another object of this invention to provide a pattern mechanismfor a dobby head which is adapted to control a plurality of differenttypes of Weave in a fabric, comprising an endless bar chain with a groupof bars therein for each type of weave in the fabric, alternate weavesrequiring oscillatory motion of the pattern chain and the other weavesrequiring forward motion of the chain.

It is a further object of this invention to provide a pattern mechanismof the class described which is adapted to control not more than twoweaves, comprising an endless chain with alternate bars for controllingthe first weave and the other bars for controlling the second weave.Means are provided for advancing the chain, step by step, two bars at atime, past the dobby fingers to actuate the same and to cause the firstweave to be controlled each step by said bars. At the end of the firstweave, a suitable reversing means is actuated to reverse the chain onebar, after which the chain is advanced two bars at a time,

as before, in a step-by-step manner, but during the second weave, theother bars will control the weave because these bars will be caused tostop beneath the dobby fingers upon each step instead of the alternatebars.

The herein disclosed mechanism is particularly adapted for use in themanufacture of crinkle cloth and towels where a. plurality of patternsare used during the weaving of the fabric. However, it is to beunderstood that the mechanism will be equally effective when used in themanufacture of other type goods, especially if this I type goodshas aplurality of weaves therein.

Some of the objects of the invention having been stated, other objectswill appear as the description proceeds, when taken in connection withthe accompanying drawings, in which- Figure l is an end elevation of adobby head with the invention secured thereto;

Figure 2 is a vertical sectional View taken along the line 2-2 in Figure1 showing the connection between the invention and a conventional boxchain;

Figure 3 is an elevation of the rear side of the dobby head taken alongthe line 33 in Figure 1;-

Figure 4 is a vertical sectional view through the box chain controllingmeans, taken along line l-Q in Figure 1, showing the multipliermechanism;

Figure 5 is a vertical sectional view taken along the line 5-5 in Figure1;

Figure 6 is a. schematic view of a complete patb-ination with theinvention;

Figure 7 is an isometric view of a fabric woven by the improved patternmechanism;

Figure 8 is an elevation similar to Figure 3 vention;

Figure 9 is a schematic View showing a complete pattern chain which isadapted to operate in combination with the form of the inventiondisclosed in Figure 8;

Figure 10 is an isometric view of a fabric, the weaving of which iscontrolled by the mechanism disclosed in Figures 8 and 9.

Referring more specifically to the drawings, the

the upper end of which has rotatably mounted therein the shaft ll uponwhich a double ended sprocket i2 is mounted. This sprocket has disposedthereon, a conventional box chain [4, comprising a plurality of linksl5, joined together by means of transversely disposed pins it. Thesepins have sleeves ll mounted therearound and between these sleeves aredisposed suitable rollers l8, l9 and 2D. The shaft ll together with thesprocket i2, is driven in timed relation to the loom. A portion of theloom frame is designated by reference character 2! (Figure 3). As thesprocket rotates, the rollers l8, l9 and 20 are caused to move over thetop side of the sprocket and beneath suitable levers 22, 23 and 2t, allof which perform functions in the operation of a dobby loom. The rollerl8, however, which operates lever 22 is an important part of theinvention, to which special attention will be given later in thespecification.

tern chain which is adapted to operat in but showing a slightly modifiedform of the innumeral ill denotes a suitable supporting bracket,

The chain M has half-round rollers 25 secured thereto at the desiredpoints. These rollers are adapted to move beneath the lower end of alever 25 which is hingedly secured to one end of another lever 21.(Figure 4). Lever 21 is fixedly secured to a shaft 28, which shaft haslevers 29 and 33 connected to the other end thereof. free end of lever29 is adapted to rest upon in 1 plier chain 3| on a shaft 32 whereas thefree end of lever 36 is adapted to fit in the grooved pulley 33 on thesame shaft to engage or disengage the driving means which drives themultiplier chain 3! in a well known manner. These parts areconventional, but it is deemed necessary to dis close this much of theold structure to more clearly describe the present invention. It shouldbe borne in mind, however, that when a roller moves beneath the lever 26that the box chain M will remain in stationary position until themultiplier chain makes one complete revolution, at which time aprojection 38 on the chain will move beneath the lever 25 to cause theshaft ii and box chain to be again set in motion.

The box chain and multiplier just described are adapted to work inconjunction with a dobby head assembly 3?. This assembly comprises apair of side frames 38 and 39 in which is journaled a suitable rockershaft ifi. Secured to the front side of this rocker shaft is an arm ii,the upper end of which is connected to upper dobby knife 43 by means ofa link (i l. The lower end of arm 4| is similarly connected to lowerdobby knife 6 by means of a suitable link i'l (Figure l). The dobbyknives 43 and t5 have their ends mounted in suitable upper and lowerslots ii) and respectively (see Figure 3), which slots are disposed inthe frames 38 and 39. Connected to the ends of the dobby knives :3 andG5 which extend through the rear side of the dobby assembly, are linksand 55, respectively, said links having their other ends connected tothe upper and lower ends of a rocker arm 57. This arm is fixedly securedaround the rearwardly projecting end of the rocker shaft 40. Anextension 56 is an integral part of the rocker arm, which extensionprojects substantially at right angles therefrom and has a slot 59therein. Adjustably mounted within this slot is the upper end of a link60 which is driven from a portion of the loom, not shown. During theoperation of the loom, the link Stis reciprocated up and down to therebyoscillate the shait ii] and to also cause the upper and lower dobbyknives 43 and 4G to reciprocate back and forth in the slots i8 and as.

Disposed between frames 38 and 38 is a transversely disposed shaftaround which the lower end of a plurality of dobby jacks 66 are adaptedto pivot. Each of these dobby jacks has a slot 5'! near its lower endwhich fits around another transversely disposed bolt 58. The upper endof each dobby jack has a plurality of notches 59 in which one end of aconnecting link it; is adapted to be fastened. The other end of thislink oper ates a loom harness.

Pivotally secured to the intermediate portions of the dobby jack 66 asat T2 is a lever '53 (Fig ure 5). The upper end of this lever haspivoted thereto as at 14, a hook l5, said hook extending to the right inFigure 5, and having its free end disposed above the upper dobby knife63. The free end of this hook is normally held out of engagement withthe reciprocating dobby :niie 43 by means of a vertically disposed rodll, the upper end of which contacts the lower intern1ediate portion ofthis hook member. The lower end of the rod I? normally rests upon lefthand end of a dobby finger It and this finger is pivoted intermediateits ends upon a transversely disposed shaft The extreme right-hand endof the ringer '58 is adapted to rest upon transversely disposedsupporting bar 69 which spans the distance between the side frames 38and 35.

The lower end of lever l3 has pivoted thereto as at 2-3 a hook 84, whichis similar to hook l5, said hook projecting forwardly and having itsright hand end disposed in operative relation to lower recipr eatingdobby knife 4 The intermediate portion of hook 33 is adapted to becontacted by the left hand end of a dobby finger which has itsintermediate portion pivotally supported by transversely disposed shaft19. The right hand end of this lever 85 is adapted to be supported bythe transversely disposed member dd.

It is evident that when the finger i8 is rotated in a counter-clockwisemanner about shaft 79, that the rod i? will be lowered and at the sametime the right hand end of the hook 15 will be lowered to al ow thereciprocating dobby knife to engage the hook and thereby rotate theupper end of dobby jack 6?: about shaft 65. This movement will raise orlower arness in the loom to cause the shed to be forms Likewise when theright hand end of finger 85 is raised to the position shown in Figure 5,the right hand end or" the hook 8 will be lowered into engagement withthe lower reciprocating dobby knife 5 and of course this will also allowthe knife to rotate the dobby jack about shaft 65 to raise or lower aharness. This is conventional structure in (101311} heads.

The fingers l8 and 85 are actuated by a suit able pattern chain 59. Thispattern chain comprises a plurality of bars 5|, em, Gib, 'Jlc, Sld, tie,ill; and Qlg, which are linked together, each bar having two rows ofpins, namely, 92 and 93, therein which are adapted to move intoengagement with the lower sides of the dobby fingers. The purpose ofplacing two rows of pins in each bar is to enable one to operate thedobby for two picks each time a bar is advanced to uppermost position.In Figure 5, a pin 92 is shown raising the right hand end of finger 35to allow the low r hook 3 3 to be lowered into the path of lower dobbyknife 65. In a like manner, the pins 93 actuate fingers T8 to lowerhooks I5.

Pattern chain 99 is mounted upon a fluted roller 95 on transverselydisposed shaft $6, said shaft having its ends journaled in bearings 9'!and 98 on the lower portions of the sidewalls 38 and 39, respectively.Fixedly secured upon the rearwardly projecting end of shaft 86 (Figures1 and 3) is a disk 96 having arcuate notches lOl in the peripherythereof. These notches are adapted to be engaged by a roller I03 on theintermediate portion of downwardly extending lever IM. This lever isrotatably mounted around the rearwardly projecting end of shaft 79 andis normally biased in a counter-clockwise manner in Figure 3 by means ofa tension spring I05. The spring Hi5 holds the roller 4G3 either incontact with a cavity ill! or against the high portion between thesenotches on the disk 00. The roller its and the disk H19 merely serve tohold the fluted roller 95 and pattern chain 30 in the proper positionwhile two picks are being made by the loom.

The projecting end of shaft 96 also has a sprocket I07 fixedly securedthereon upon which a sprocket chain I08 is mounted. The chain is alsomounted upon a larger sprocket I09 said sprocket being rotatably mountedaround stud IIO, which stud is mounted in bracket III fixed to thesidewall of the dobby head. Secured to the face of sprocket I06 is aratchet wheel M4, the teeth of which are adapted to be engaged by theprojecting end of a hook member II 5. This hook projects to the left inFigure 3 and is adjustably secured to a bracket IN by any suitable meanssuch as set screw H8. It will be noted that the bracket has itsleft-hand end adjustably and pivotally secured as at H0 within slot I20.This slot is disposed in the lower portion of rocker arm 51. As the arm51 oscillates back and forth about rocker shaft 40, the righthand end ofhook I I5 engages the teeth in ratchet wheel II4 to thereby cause thesprockets I09 and I01 to rotate in a counter-clockwise manner. Due tothe position of the hook on the free end of the member II5, and due tothe gearing, the shaft 96 and its associated fluted roller 95 is rotatedsuificiently to move a bar QI to upright position for each oscillationof the rocker arm 51. In other words, the loom performs two picks eachtime the rocker shaft 40 is oscillated; consequently it is necessary tobring bar 9| to upright position beneath the fingers I8 and each time anoscillation is made. The structure described by the reference characters95 to II 5 inclusive might be broadly termed as the means for advancingforwardly the pattern chain 50.

In order to eliminate the necessity of having an excessively longpattern chain, means have been provided whereby the pattern chain willbe moved forwardly for a plurality of bars and then means will beemployed for returning the chain to a previously occupied positionduring one half of an oscillation of the rocker shaft 40 to therebyposition the bars so that they can be used over again. This restoringmechanism comprises a ratchet wheel I25, the lower portion of which isadapted to be engaged at times by the hook on the end of member I26,said ratchet being an integral part of sprocket I09. The member I26 isadjustably mounted in bracket II! by means of set screw I21. When apredetermined number of bars 0I have been rotated beneath the fingers I8and 85, the free end of hook I26 is moved upwardly into engagement withthe teeth in ratchet wheel I25 and then upon the clockwise oscillationof rocker arm 57 and crank shaft 40, the reverse rotation will beeffected upon the sprockets I09 and IN and also upon shaft 96, roller 95and pattern chain to cause the chain to be restored to a preoccupiedposition. Due to the mechanical structure and arrangement of hooks H5,and I26, and their associated ratchets, the pattern chain may be movedforwardly by hook II 5, one bar for each oscillation of the rocker arm,whereas it may be reversed two bars upon each oscillation when hook I26is in engagement. After this restoring has taken place the member H5 andits associated hook is adapted to again assume the position as shown inFigure 3 at which time the chain 90 will again resume its forward orcounter-clockwise rotation.

The means for causing the hook on the end of member I26 to engage theratchet wheel I25, however, will now be described. It will be noted thatthe intermediate portion of hook II5 has connected thereto a tensionspring I28, and the upper end of this tension spring is secured to thefree end of a lever I29, said spring acting as a resilient link (Figure3). Lever I29 is pivoted as at I30 in slot I3I of bracket I32. Disposedon the lower intermediate portion of this lever is a cam surface I33,said cam surface being adapted to be contacted at times by laterallyprojecting pins I34 and I35 which project from the inner face of aratchet wheel I36. This ratchet wheel is rotatably mounted around stud I31 which likewise is secured to bracket I32. The teeth in the ratchetI36 are engaged by the hook on the free end of a member I38, said memberhaving its left-hand end (Figure 3) pivoted as at I30 in slot I40. Thisslot is cut in the upper portion of rocker arm 51. A torsion spring I4Inormally tends to hold the free end of hook member I38 into engagementwith the teeth of ratchet I36.

It is seen that as the rocker arm 51 and the rocker shaft 40 oscillatethat the ratchet I36 will be advanced notch by notch, that is theratchet will be advanced one notch for each complete oscillation of therocker arm. In order to hold the ratchet wheel I36 in the positionduring the operation of the hooked member I38, a suitable roller I45 hasbeen disposed intermediate the ends of a lever I46, said lever beingpivoted as at I30 to bracket I32. The free end of the lever I46 normallyis pulled in a counterclockwise manner about point I30 by means of atension spring I48. This spring holds the roller I45 in one of aplurality of arcuate notches I50 which are disposed in the peripheryof adisk I 5I, said disk being fixedly secured to the face of ratchet wheelI36.

It can be seen by referring to Figure 3 that each time the right-handend of hook member I36 makes a complete oscillation that the mechanismpreviously described will operate to bring another bar 9| to uppermostposition upon the fluted roller and in operative rotation with fingersI8 and 85.

Since there are two pins I34 and I35 disposed in the face of ratchetI36, and since there are only six notches in the periphery thereof, itis also evident that only three bars can be advanced before one of thepins I34 or I35 will rise beneath sequently when the rocker arm isoscillated in a clockwise direction (Figure 3) the chain 90 will bereversed a distance of two bars and be restored to original position. Inother words, when the hook member H5 is disposed in its extremeright-hand position in Figure 8, with its free hooked end in engagingposition with ratchet IM, the hook will be disposed a slight distance tothe right of the teeth in this ratchet; consequently, when the rockerarm oscillates to the left the hook will travel a short distance to theleft before engaging the teeth to rotate the same. The hook on the endof member I26 is so positioned that it will engage the teeth to rotateratchet I251 immediately upon oscillation of rocker arm to the left,that is when the hook member is raised to engaging position. There is nolost motion between the hook member H5 and the teeth in ratchet I25. Ofcourse when one of the pins I34 or I35 rides out from beneath weaveis'being made in a cloth. In the present instance three different barsare moved into engaging relation with dobby fingers i8 and 85. Then thebars are reversed to original position to allow these same bars to beused over again and again. Since each bar represents two loom picks, itnaturally follows the following set-up is made for six pick repeats.

Where it is necessary to transfer from a repeat weave into another typeof weave then the reversing process of the chain must be renderedinoperative and forward motion only imparted to the chain 90 while thisextra weave is being made. In order to render inoperative this reversemotion, it is necessary to lift the hook member I38 out of engagementwith ratchet I36. This lifting is effected by an inwardly and laterallyprojecting end I which is disposed beneath the intermediate portion ofmember E38, and which forms an integral part of a lever 56. Lever F56has its intermediate portion mounted for oscillation around stud I37.The lever 556 also projects a substantial distance to the right of studI31 and has the upper end of a link I58 secured thereto, the lower endof which is pivotally secured to the upwardly extending end of lever 22previously described (Figures 1, 2 and 3). Upon the completion of therepeat weave, if it is desired to continue the forward rotation of thechain in one direction only, a ball I 8 (see Figures 1 and 2) will ridebeneath the lowermost end of lever 22 to cause the same to be rotated ina clockwise manner in Figure 2. This will rotate the lever I56 in aclockwise manner in Figure 3 to cause the inwardly projecting end I55 tobe moved beneath the intermediate portion of hooked lever I33 and liftits hook out of engagement with ratchet I38. A torsion spring IE0 isprovided for normally rotating the lever I56 in a counter-clockwisemanner to the position shown in Figure 3. As long as the roller i8remains beneath the end of lever 22 only forward motion can be impartedto the pattern chain because a pin I34 or 35 cannot be moved beneath thecam surface I33 of lever I29 to cause the free end of said lever to liftreversing hook 525 into engagement with ratchet I25. During this forwardmotion of the chain Eifl the hook on the end of member H5 will beengaging the teeth in ratchet I I l and thus advancing one bar I foreach oscillation of the rocker arm.

Let us suppose that it is desired to weave a towel such as shown inFigure '7 which is designated by reference character I 32. Within thistowel there are three different kinds of weaves, namely, the reverseterry weave 563 on each end thereof, border weave 5%, regular terryweave I85 and another border I66. Assuming that we are beginning at thenear end of the towel as shown in Figure 7 in the reverse terry weaveI63. At this time the bar 9i will remain beneath the fingers l8 and 35for two picks; then the next bar am will move to uppermost operativeposition and remain there for two picks and then a bar QIb will move tothe uppermost position and remain for the same length of time. At thistime, the bars will be restored to the position shown in Figure 6 bymeans of restoring hook I25 in Figure 6 previously described. Therestoration takes place between picks. This step-by-step forward motionof the chain and the one step restoring motion will be repeated untilthe border I64 is reached, after which a roller I8 will move beneath thelower end of lever 22 to cause the lever I56 (Figure 3) to disengage thehook memher I 33. Then the chain will continue its forward motion overtwelve successive bars QIc, representing twenty-four picks which will bedisposed within this border portion. At this time the roller I8 will becaused to move from beneath the lower end of lever 22 at which time thebars QId, Elle and 9 if will move back and forth beneath the fingers l8and 85, during the weaving of regular terry portion IE5 in the samemanner that the bars HI, .lIa and Sib moved while the reverse terry wasbeing woven. Upon the completion of the regular terry I another borderit? is woven by twelve successive bars 9 lg in the same manner that thebars sic were used to weave the previous border 5 and upon thecompletion of the border, the reverse terry portion I53 on the far endof the towel will be woven in the same manner previously described.

Figures 8, 9 and 10 show a modified form of the invention which isemployed for weaving a fabric having not more than two types of weaves.Figure 10 shows a towel 5'55 having a terry weave Il't on each endthereof as well as a terry weave H6 disposed between two border weavesI17.

An especially constructed pattern chain I18 is employed for weaving thistype of fabric. This pattern chain comprises a plurality of alternatelyspaced bars I79 and a plurality of alternately spaced bars 333, eachhaving pins 92 and 53 therein for operating dobby fingers l8 and 35. Thebars 579 are adapted to control the mechanism for veaving the terryweaves I76 whereas the bars I86 are adapted to control the border weavesIii. Therefore, when the terry weave I73 is being woven, it is necessaryto rotate the fluted roller 95 for a distance equal to two links of thechain for every two loom picks. By doing so, then a link I79 will bedisposed in the uppermost operative position upon each oscilla tion ofthe rocker arm 57. weave has been completed and it is desired to weave aborder area I'I'I', it is then necessary to provide means for reversingthe chain a distance of one link so that a bar I60 will be disposed inuppermost position and beneath the fingers I8 and 35. After this is donethe chain will resume its normal forward movement with each movement ofthe chain being equal to two bars. Therefore, only the alternate barsI80 will stop beneath the fingers l8 and 35 until the chain is againreversed for an odd number of bars.

The structure used for moving the chain I'IB a distance of two bars whenthe terry weave H6 is being woven is similar to that in the precedingform. Revision is made in hook members I and i8! and also the point II9, where the bracket II! is secured to the lower end of the rocker arm,has been lowered, thereby giving the hooked member I85 a greater throw.Consequently, the

oscillation of the rocker arm iii will cause the of the rocker arm 51and upon the engagement of the hook on this member with the ratchet I25that this ratchet will only be reversed one notch instead of two as inthe preceding form. In other words, when hook member I8? is disposed inits extreme right hand position in Fig- When the terry ure 8 with itsfree hooked end moved up into engaging position, this hook will bedisposed a slight distance to the right of the teeth in ratchet 25;consequently when the rocker arm oscillates to the left the hook willtravel a short dis-' tance to the left before engaging the ratchet torotate the same. The reversal of the ratchet as heretofore stated iseffected when a transfer is desired to be made from the terry weave tothe border weave or vice versa.

In order to throw the hooked end of member 187 into engagement withratchet I25 at the proper time, a roller it of box chain 44 such asillustrated in Figures 1 and 2 is caused to be moved beneath the lowerend of arm 22 at the proper time. The lever 22 will then be'rotated in aclockwise manner in Figure 2, which, in

, turn, will cause the lever [56 to rotate in a clock wise manner inFigure 8. This motion of lever I56 will be transmitted to bracket H1 andthe hook member it! through a spring link l2l3av The assembly comprisingmembers HT, I85 and I81 will be rotated in a counter-clockwise movementabout pivot point M9 to cause the hook on the end of member it! toengage the ratchet I25. Special attention is called to the fact that theupper hook I35 is so positioned that it will pull the chains H8forwardly the distance of two bars for each oscillation of the rockershaft; whereas the lower hooked member 87, when it is caused to engagewith its ratchet, will reverse the chain only one link for eachoscillation of the rocker shaft.

In the drawings and specification, there has 7 set foith a preferredembodiment of the invention and although specific terms are employed,they are used in a generic and descriptive sense only and not for thepurpose of limitation, the scope of the invention being set forth in theappended claims.

We claim:

1. A pattern mechanism for a loom dobby head having dobby fingers forcontrolling the weaving of a fabric and also having a rocker arm for theoperation of said head, comprising a roller disposed below said fingers,a pattern chain having a plurality of linked bars therein disposed onsaid roller with the uppermost bar normally in engagement with thefingers, a ratchet operatively connected to said roller for driving thepattern chain in one direction, a second ratchet operatively connectedto said roller for driving the pattern chain in the opposite direction,a pawl for each of said ratchets and being driven by said rocker arm,the pawl for said first ratchet being normally engaged to rotate thepattern chain forwardly upon each oscillation of the rocker arm and thepawl for said second ratchet being normally disengaged, a box chain andmeans controlled by said box chain for disengaging said first pawl andengaging said second pawl with their respective ratchets to cause thepattern chain to rotate reversely, the pawls engaging their respectiveratchets at diiferent points in their stroke to thereby rotate theratchets different amounts.

2. A pattern mechanism for a loom dobby head having dobby fingers forcontrolling the weaving of a fabric and also having a rocker arm for theoperation of said head, comprising a roller disposed below said fingers,a pattern chain having a plurality of linked bars therein disposed onsaid roller with the uppermost bar normally in engagement with thefingers, a ratchet operatively connected to said roller for driving thepattern chain in one direction, a second ratchet operatively connectedto said roller for driving the pattern chain in one direction, a pawlfor each of said ratchets and being driven by said rocker arm, the pawlfor said first ratchet having an effective stroke while engaging itsratchet to advance the pattern chain forwardly upon each oscillation ofthe rocker arm a predetermined distance and the pawl for said secondratchet having an effective stroke while engaging its ratchet to reversethe pattern chain a distance differing from the amount of forwardmovement of the first ratchet, a box chain, means controlled by said boxchain for disengaging said first pawl and engaging said second pawl withtheir respective ratchets to cause the pattern chain to rotatereversely, and means for restoring said pawls to normal position aftersaid reversal has been effected to cause the pattern chain to againresume its forward rotation.

3. In a dobby head for looms having dobby fingers, dobby knives, jacksand a rocker arm operatively connected to the dobby knives for impartingreciprocatory motion thereto, a roller having a pattern chain mountedthereon, a box chain, a pair of ratchet Wheels operatively connected tothe roller for driving the same, a pair of pawls. rigidly connected toeach other and pivotally mounted at one end of the rocker arm, meansnormally holding one of the pawls in engagement with one of the ratchetwheels for advancing the roller and its pattern chain in one direction,operative connections between the box chain and said pawls for shiftingthe position of said pawls relative to the ratchet wheels to cause theother of said pawls to engage its associated ratchet wheel uponoscillation of the rocker arm to impart reverse rotation to the patternchain, the effective stroke of the two pawls on their ratchets beingdifferent to cause the amount of advance and reverse of the patternchain to differ from each other.

4. In a dobby head for looms having dobby fingers, dobby knives, jacksand a rocker arm operatively connected to the dobby knives for impartingreciprocatory motion thereto, a roller having a pattern chain mountedthereon, a box chain, a ratchet wheel operative connected to the roller,a member pivotally mounted on the rocker arm and having a pair of pawlsprojecting therefrom and being disposed on opposed sides of the ratchetwheel, means for normally holding one of the pawls in .a position torotate the ratchet wheel in one direction upon oscillation of the rockerarm, a box chain and operative connections between the box chain andsaid pawls for shifting the position of the pawls to cause the other ofsaid pawls to engage the ratchet wheel upon oscillation of the rockerarm to drive the ratchet wheel and the roller in a reverse direction,the efiective stroke of the two pawls on their 1 ratchets beingdifferent to cause the amount of

